1. Field of the Invention
This invention pertains generally to printing form and variable data, and more particularly to high speed printing of form and variable data in a single operation.
2. Description of Related Art
Documents such as a billing statement or account statement have two components; the form containing the same image on every sheet and the variable data such as customer data which has different information on every sheet. Form images may include multiple color graphics and indicia such as a company logo or lines for summation or detachment, or alpha numeric information such as company name or payment instructions. Variable customer data is unique for each sheet of a document or customer statement and may be customer account information, a summary of use or calculation of charges. Variable data is typically printed in a single color such as black. The number of sheets in a customer statement or document can vary. A typical customer statement is about 1 to 16 sheets but in exceptional cases can be over 100 sheets or even 1,000 sheets.
FIG. 1 illustrates an existing process 10 for preparing customer statements and documents. A bulk roll of paper 12, typically 36 inches wide, is fed through offset web press 14 to print form information. An offset press has a platform that handles bulk paper and separate print modules with each module having an offset plate for a unique color. An example is an offset press with four print modules set up as a four color CMYK process printer. Another example is an offset press with multiple spot color print modules. High speed offset web press 14 can produce color forms at the rate of 1000 feet per minute since the image to be printed by each module remains the same for all forms. Because most offset printing is done using water and ink on plates, additional equipment for drying the paper and setting the ink is required (not shown). An example of equipment used for this purpose is a Didde D-900 web press or a Zirkon 7221 web press.
Forms are typically printed two to four across on offset web press 14. The paper is then fed through a slitter winder 16 where the printed forms are wound on narrow rolls 18. These printed form rolls are then handled, stored and transported at block 20 with associated handling costs. Printed forms may also be processed and handled as fanfold stacks. In many operations, printed form rolls 18 are prepared by outside vendors and shipped to the document processing center. An inventory of printed form rolls 18 for each client is typically stored in a controlled environment at the statement processing center prior to printing customer statements.
At the statement processing center, printed form roll 18 is taken from storage and unwound at block 22 and fed through a single color variable data printer 24. A controller 26 is connected to a variable customer database 28 and printer 24. Controller 26 accesses customer database 28 and directs variable data printer 24 to print variable customer data on the forms. The customer data is usually printed in black with a high speed laser printer. A typical high speed laser printer can print medium quality (300 dpi) variable data at speeds up to about 250 feet per minute. An example of this equipment is an IBM Infoprint 4000 or an Oce VarioStream 7000 printer. The speed of the laser printer 24 is limited because the image printed on each form sheet is unique and the number of sheets in each customer statement varies. Also the laser printer prints the customer statements consecutively one sheet at a time.
The customer statements from printer 24 are typically prepared for further processing by stacker 26 to form stacks of fanfold customer statements 28. The remaining steps of cutting customer statements into sheets, collating and inserting into envelopes for mailing is not illustrated in FIG. 1.
A conventional desktop ink jet printer using CMYK cartridges on a scanning print head is capable of printing color form images and variable data simultaneously, but prints much slower than laser printers because the print head must scan the entire sheet to print both form images and variable customer data. This results in a slower process and much higher cost per customer statement than using high speed laser printers.
A high speed laser printer can be configured to print additional spot color such as a logo or line, but the speed is still limited to that of a laser printer.
A digital offset press can be configured to print form and variable data, but the cost of operation is very high and the throughput, in the range of about 10,000 documents per hour, is too slow for production statement printing.
What is needed is a high speed printing apparatus and method for producing multiple color form images and single color variable customer data in a combined process to increase printing speed and reduce handling and storage costs for forms and customer statements.